CFD for two continuous annealing furnaces

The following master's thesis in engineering physics was performed for the company Outokumpu. The purpose of this project was to examine if CFD can be used as an alternative method to study the internal pressure distribution of two continuous annealing furnaces. Attaining a positive pressure inside the two furnaces is of high importance to reduce the ingress of air from the surroundings. To achieve this two three dimensional models were developed through drawings and manual measurements. Initial and boundary conditions were obtained for a standard annealing case by analyzing measurement data. Simulation results were compared with measurement data to determine the accuracy and reliability of the CFD models. It was determined that the stainless steel strip passing through the furnaces acts as a barrier hindering the flow of the flue gases. This highlights the importance of burner placement inside the furnace to achieve the desired internal pressure. A proposal of utilizing burners on both sides of the strip resulted in a increased pressure. From measurement data it was observed that the amount of oxygen in the furnace atmosphere decreased which implies a reduction of the ingress of air from the surrounding environment. Given these results and the insight the CFD models provided, this report highlights the potential of using numerical methods to enhance the operational conditions of the two continuous annealing furnaces.